Model Boat Mayhem

The Shipyard ( Dry Dock ): Builds & Questions => Submarines => Topic started by: Happy Harry on June 26, 2010, 04:24:11 pm

Title: U47 In Saltwater
Post by: Happy Harry on June 26, 2010, 04:24:11 pm
Hello All,

I've been searching the forum on an answer on this and cant seem to find one. My nearest model lake is salt water fed (In Redcar NE England), whilst I suspect this may be fine for surface vessels is it ok to run my U47 Static diver there? I suspect not because of the damage salt water can do and I seem to remember a difference in buoyancy(?) with salt and fresh water.

Any help is much appreciated, and if I'm incorrect on the buoyancy issue please let me know.

Many Thanks
Title: Re: U47 In Saltwater
Post by: Subculture on June 26, 2010, 05:04:42 pm
Your signal will disappear almost immediately you run beneath the surface.

Some modellers have got around this by running a stiff brass aerial that sticks up a foot or so high. This gives you a reasonable amount of depth to dive. The aerial can be painted to protect it from the elements. You will need to shorten your RX aerial accordingly to accommodate for the length of the brass rod

Anything metallic will also suffer, so you need to be religious in hosing down your boat in fresh water after a run, and greasing everything up well before and after.
Title: Re: U47 In Saltwater
Post by: hollowhornbear on June 26, 2010, 05:05:21 pm
also the radio will not penetrate saltwater very far, i seem to remember reading. the more experienced submariners on here will soon have an answer for you, or correct me if i'm wrong.
Title: Re: U47 In Saltwater
Post by: hollowhornbear on June 26, 2010, 05:06:31 pm
there you go Subculture beat me to it.
Title: Re: U47 In Saltwater
Post by: dreadnought72 on June 26, 2010, 05:14:19 pm
In addition to the salt stopping radio signals, salt water is denser than fresh by about 2.5%. Your sub will float a wee bit higher.

Andy
Title: Re: U47 In Saltwater
Post by: Happy Harry on June 26, 2010, 05:30:13 pm
Guys,

Thankyou so much, advice noted. I think I will travel to find fresh water instead, a bit too much time, effort and expense for me to ruin it. Thankyou all again.

Regards
Title: Re: U47 In Saltwater
Post by: RonP on June 27, 2010, 11:33:52 pm
A radio signal from the sort of equipment we use will theoritically transmit through water to an indefinate depth, thats theory, however the thing that causes us problems are suspended and disolved solids. The sea has a high concentrate of dissolved solids (salt) so a depth of only a few inches can be achieved. Brackish water (like some inlets) is not so bad but only about a foot is safe (ish). The most powerful radio control unit ever made was the old Futaba "M" series on 27meg AM. It is in fact illegal to use now as its output was higher than current limits. If you can get hold of one (and they are still out there)you will find that this may well solve your problem, I have sailed in salt water to a depth of 3 feet or more with one of these units and down over 15 feet in a diving pool (Chlorine being the dissolved solid). Run your ariel wire up a periscope and seal of the end of the wire with some epoxy and DO use some sort of failsafe mechanism to bring boat up if loss of signal and all should be well. best of luck----all is not lost.
Ron Perrott
Title: Re: U47 In Saltwater
Post by: Subculture on June 28, 2010, 09:16:42 pm
That set would be nearly as old as me. They seem to be getting collectable now, and once that happens the price creeps up and up.

The one and only time I unwittingly operated a sub in salt water was at Southend in Southchurch Park. I didn't know the pond was feed from the sea (although I should have guessed bearing in mind the location) and as soon as my Seehund slipped beneath the surface it went ape and the failsafe blew the ballast tank. That was with my old Fleet set.
Title: Re: U47 In Saltwater
Post by: RonP on June 30, 2010, 05:12:22 pm
That set would be nearly as old as me.
Oh I REALLY wish you hadn't said that.
Title: Re: U47 In Saltwater
Post by: Patrick Henry on June 30, 2010, 08:01:41 pm
Showing your ages, gentlemen?   %)